Recording sound on wire



J1me 1950 w. A. BRASTAD ETAL 2,510,923

RECORDING SOUND 0N WIRE Original Filed March 3, 1945 /NVE/VTOR.S.'- WILLIAM A. BRASTAD LESTER F. BOROHARDT d TTORHEY Patented June 6, 1950 UNH'ED STATES FTENT ()FFICE.

RECORDING SOUND N WIRE William A. Brastad and Lester F. Borchardt, Minneapolis, Minn, assignors to General Mills, Inc., a corporation of Delaware Original application March 3, 1945,- Serial No.

580,329. Divided and this application February 11, 1949, Serial No. 75,758

Claims.

This invention relates to recording sound on wire, tape, disks, and like paramagnetic mediums.

This application is a division of our co-pending application filed March 3, 1945, Serial No. 5 of the various forms of heads which may be used 580,820, now U. S. Patent No. 2,483,398, issued in the invention and is fully described in the co- Oct. 4, 1949, entitled Recording sound on Wire. pending parent application Serial No. 580,820, Heretofore recordings of sound on wire have now U. S. Patent No. 2,483,398, issued Oct 4, been made by transmuting the energy of sound 1949. by means of a suitable microphone into an alter- In the present setup a stepdown transformer is hating or pulsating current which then acts used to lower the voltage and increase the magnithrough a suitable electromagnet to produce a tude of current put out by the amplifier F. The corresponding pulsating magnetic field through stepdown ratio of this transformer, however, is which the paramagnetic material, as wire, ribbon, a matter of choice, depending largely on the curdisk, etc., passes to receive a magnetic recordrent and voltage output of the amplifier. ing. For our purposes we have found that a speed By means of this invention the recording can of 5 ft. per second on wire W is suitable both be done without the use of electromagnets or of for recording and reproducing. This, however, any paramagnetic material other than that in may be varied considerably. the wire or other medium on which the record is In the setup, as shown in Fig. with the remade. Instead, the recording is done by passcording head shown or with the head of Fig. 2, ing the recording current into and out of said the wire W moves contacting the conductors or medium. electrodes and current enters the wire W through An object of this invention is to provide a one of the conductors and leaves through the simple and efiicient method of and apparatus for other. Alternations of this current in the output recording sound on Wire. of the amplifier are recorded on the wire W and This and other objects as will hereinafter apcan be picked up, either at once or later, by a pear, are accomplished by this invention, whichsuitable electromagnetic reproducer 2B, which in is fully described in the present application, and turn generates an alternating current in the shown in the accompanying drawings in which: leads 22. This current then being amplified in Figure 1 is a diagrammatic view of the appathe amplifier L is converted into sound in the ratus for recording sound on wire and for reloud speaker M. producing the same; and Applicants theory of how the recording oc- Fig. 2 is a perspective view of a form of recordcurs, but by which they do not wish to be bound, ing head for use in this invention. is as follows: A biasing current, preferably of The embodiment diagrammatically illustrated the order of one ampere, is supplied to the leads in Fig. 1 consists of reels A and B with a wire J by the battery H and on this current is super- W wound thereon which is unreeled from the imposed a pulsating or alternating audio curreel A, passes around sheaves C, D, and is wound 7 rent by the secondary coil of the transformer up on the reel B. Apparatus for operating the G. These combined currents flow through elecreels A and B, to reel the wire from reel A to trodes and thence through the steel wire W on reel B and then from reel B to reel A, is well which a recording is to be made. Because of the known in this art and is not illustrated as it relatively large electric currents and the small forms no part of the present invention. cross-sectional area of the current path through Sound to be recorded on the wire W acts on the steel wire W, the magnetic fields generated the microphone E causing it to generate an elecby these electric currents are sufiiciently strong trical voltage which varies in frequency and amto leave a magnetic sound record on the moving plitude corresponding to said sound. The voltwire. It is to be understood applicants are not age is suitably amplified by the amplifier F terlimited to D. C. biasing but may use any other minating in transformer G. The resulting curwell known form such as supersonic. rent is then combined with a biasing current from The recording head shown in Fig. 2 has the a suitable source such as battery H, and passes wire W4 passing between electrodes shown in through the leads J to the recording head K the form of metal rollers 50, 62 which are suitwhich causes the current to pass through the ably journalled on studs 64, 66, respectively, and recording wire W thereby creating a magnetic 55 retained by set collars 65, and set screws 61. The

stud 66, is attached to a base 68, which is secured by screws to a block of insulation 10, which in turn is secured by screws 12, to a part of the recorder frame 14. The stud 64 is carried. by a member 16 which is hingedly mounted on a pin 18, secured in the block of insulation 10. A spring 80 yieldably forces the roller 60 against the wire W4, thereby gripping the wire between the rollers. The rollers can be powered so as to drive the wire W4 or the wire can be drawn by other means thus causing the rollers to rotate about their axes as idlers. An adjusting screw 8| is an electric insulator to prevent current short circuiting the rollers 60, 62.

Electric current fluctuations to be recorded are made to flow to the rollers 60 and 62 by means Of suitable brushes 82 and 89, of carbon or the like, held in tubular lugs 83 and 84, and yieldably pressed against the peripheries of the roller by means of a spring 86, 90, adjustably held by screws 88 and 9|.

As the recording is made, the wire W, in Fig. 1, feeds from the reel A over sheaves C, D and past the recording head K to the reel B. The wire can be played by means of the reproducing head immediately after recording or at any later time by running the wire in the same direction. While we have discussed only a recording medium in the form of a wire, it will be realized that this method may be satisfactorily employed with other forms of recording media such as tapes, disks, and cylinder.

While we have shown and described but a few forms of our apparatus, it will be apparent that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as defined by the appended claims.

We claim as our invention:

1. Apparatus for recording sound on moving paramagnetic wire comprising electrodes spaced laterally of the wire and in contact therewith, the wire passing between the electrodes, means for developing from sounds to be recorded a varying electrical voltage corresponding to the sounds, and means for applying said electrical voltage to the electrodes thereby causing a varying current to flow through the portion of wire between said points to record the sound magnetically on the wire.

2. Apparatus for recording sound on a paramagnetic wire comprising electrically conducting rollers in contact with the wire, means for moving a wire between said rollers with the rollers in contact with laterally spaced points on the wire, means for developing from sounds to be recorded a varying electrical voltage corresponding to the sounds, and means to apply said electrical voltage to the rollers thereby causing a varying current in the wire between rollers to record the sound magnetically on the wire.

3. Apparatus for recording sound on paramagnetic wire comprising electrically conducting rollers, means for longitudinally moving a wire in contact therewith, means for yieldably pressing said rollers toward the wire, means for developing from sounds to be recorded a varying electrical voltage corresponding to the sounds, and means for applying said electrical voltage to the rollers thereby causing a varying current to flow in the wire between the rollers to record the sound magnetically on the wire.

4. Apparatus for recording sound on paramagnetic wire comprising electrically conducting rollers journalled on studs on opposite sides of the wire, means for moving a wire between said rollers and in contact therewith, means for yieldably pressing said studs toward the wire, means for developing from sounds to be recorded a varying electrical voltage corresponding to the sounds, and means for applying said electrical voltage to the electrodes thereby causing a varying current in the wire between the rollers to record the sound magnetically on the wire.

5. Apparatus for recording sound on paramagnetic wire comprising spaced electrodes consisting of electrically conducting rollers journalled on studs on opposite sides of the wire, means for moving a wire between said rollers and in contact therewith, one of said studs being mounted to swing about an axis, means for yieldably pressing said studs toward each other, means for developing from sounds to be recorded a varying electrical volt-age corresponding to the sounds, and brushes bearing on the rollers connected to the means for developing the electrical voltages and applying to the rollers the electrical voltage to cause varying current to flow in the wire between the rollers thereby magnetically recording the sound on the wire.

WILLIAM A. BRASTAD. LESTER F. BORCHARDT.

No references cited. 

